[tcpdump] / smbutil.c

/*
 * Copyright (C) Andrew Tridgell 1995-1999
 *
 * This software may be distributed either under the terms of the
 * BSD-style license that accompanies tcpdump or the GNU GPL version 2
 * or later
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifndef lint
static const char rcsid[] _U_ =
     "@(#) $Header: /tcpdump/master/tcpdump/smbutil.c,v 1.32 2004-12-28 22:29:45 guy Exp $";
#endif

#include <tcpdump-stdinc.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "interface.h"
#include "extract.h"
#include "smb.h"

extern const u_char *startbuf;

/*
 * interpret a 32 bit dos packed date/time to some parameters
 */
static void
interpret_dos_date(u_int32_t date, struct tm *tp)
{
    u_int32_t p0, p1, p2, p3;

    p0 = date & 0xFF;
    p1 = ((date & 0xFF00) >> 8) & 0xFF;
    p2 = ((date & 0xFF0000) >> 16) & 0xFF;
    p3 = ((date & 0xFF000000) >> 24) & 0xFF;

    tp->tm_sec = 2 * (p0 & 0x1F);
    tp->tm_min = ((p0 >> 5) & 0xFF) + ((p1 & 0x7) << 3);
    tp->tm_hour = (p1 >> 3) & 0xFF;
    tp->tm_mday = (p2 & 0x1F);
    tp->tm_mon = ((p2 >> 5) & 0xFF) + ((p3 & 0x1) << 3) - 1;
    tp->tm_year = ((p3 >> 1) & 0xFF) + 80;
}

/*
 * common portion:
 * create a unix date from a dos date
 */
static time_t
int_unix_date(u_int32_t dos_date)
{
    struct tm t;

    if (dos_date == 0)
        return(0);

    interpret_dos_date(dos_date, &t);
    t.tm_wday = 1;
    t.tm_yday = 1;
    t.tm_isdst = 0;

    return (mktime(&t));
}

/*
 * create a unix date from a dos date
 * in network byte order
 */
static time_t
make_unix_date(const u_char *date_ptr)
{
    u_int32_t dos_date = 0;

    dos_date = EXTRACT_LE_32BITS(date_ptr);

    return int_unix_date(dos_date);
}

/*
 * create a unix date from a dos date
 * in halfword-swapped network byte order!
 */
static time_t
make_unix_date2(const u_char *date_ptr)
{
    u_int32_t x, x2;

    x = EXTRACT_LE_32BITS(date_ptr);
    x2 = ((x & 0xFFFF) << 16) | ((x & 0xFFFF0000) >> 16);
    return int_unix_date(x2);
}

/*
 * interpret an 8 byte "filetime" structure to a time_t
 * It's originally in "100ns units since jan 1st 1601"
 */
static time_t
interpret_long_date(const u_char *p)
{
    double d;
    time_t ret;

    TCHECK2(p[4], 4);

    /* this gives us seconds since jan 1st 1601 (approx) */
    d = (EXTRACT_LE_32BITS(p + 4) * 256.0 + p[3]) * (1.0e-7 * (1 << 24));

    /* now adjust by 369 years to make the secs since 1970 */
    d -= 369.0 * 365.25 * 24 * 60 * 60;

    /* and a fudge factor as we got it wrong by a few days */
    d += (3 * 24 * 60 * 60 + 6 * 60 * 60 + 2);

    if (d < 0)
        return(0);

    ret = (time_t)d;

    return(ret);
trunc:
    return(0);
}

/*
 * interpret the weird netbios "name". Return the name type, or -1 if
 * we run past the end of the buffer
 */
static int
name_interpret(const u_char *in, const u_char *maxbuf, char *out)
{
    int ret;
    int len;

    if (in >= maxbuf)
        return(-1);     /* name goes past the end of the buffer */
    TCHECK2(*in, 1);
    len = (*in++) / 2;

    *out=0;

    if (len > 30 || len < 1)
        return(0);

    while (len--) {
        TCHECK2(*in, 2);
        if (in + 1 >= maxbuf)
            return(-1); /* name goes past the end of the buffer */
        if (in[0] < 'A' || in[0] > 'P' || in[1] < 'A' || in[1] > 'P') {
            *out = 0;
            return(0);
        }
        *out = ((in[0] - 'A') << 4) + (in[1] - 'A');
        in += 2;
        out++;
    }
    *out = 0;
    ret = out[-1];

    return(ret);

trunc:
    return(-1);
}

/*
 * find a pointer to a netbios name
 */
static const u_char *
name_ptr(const u_char *buf, int ofs, const u_char *maxbuf)
{
    const u_char *p;
    u_char c;

    p = buf + ofs;
    if (p >= maxbuf)
        return(NULL);   /* name goes past the end of the buffer */
    TCHECK2(*p, 1);

    c = *p;

    /* XXX - this should use the same code that the DNS dissector does */
    if ((c & 0xC0) == 0xC0) {
        u_int16_t l = EXTRACT_16BITS(buf + ofs) & 0x3FFF;
        if (l == 0) {
            /* We have a pointer that points to itself. */
            return(NULL);
        }
        p = buf + l;
        if (p >= maxbuf)
            return(NULL);       /* name goes past the end of the buffer */
        TCHECK2(*p, 1);
        return(buf + l);
    } else
        return(buf + ofs);

trunc:
    return(NULL);       /* name goes past the end of the buffer */
}

/*
 * extract a netbios name from a buf
 */
static int
name_extract(const u_char *buf, int ofs, const u_char *maxbuf, char *name)
{
    const u_char *p = name_ptr(buf, ofs, maxbuf);
    if (p == NULL)
        return(-1);     /* error (probably name going past end of buffer) */
    name[0] = '\0';
    return(name_interpret(p, maxbuf, name));
}


/*
 * return the total storage length of a mangled name
 */
static int
name_len(const unsigned char *s, const unsigned char *maxbuf)
{
    const unsigned char *s0 = s;
    unsigned char c;

    if (s >= maxbuf)
        return(-1);     /* name goes past the end of the buffer */
    TCHECK2(*s, 1);
    c = *s;
    if ((c & 0xC0) == 0xC0)
        return(2);
    while (*s) {
        if (s >= maxbuf)
            return(-1); /* name goes past the end of the buffer */
        TCHECK2(*s, 1);
        s += (*s) + 1;
    }
    return(PTR_DIFF(s, s0) + 1);

trunc:
    return(-1); /* name goes past the end of the buffer */
}

static void
print_asc(const unsigned char *buf, int len)
{
    int i;
    for (i = 0; i < len; i++)
        safeputchar(buf[i]);
}

static const char *
name_type_str(int name_type)
{
    const char *f = NULL;

    switch (name_type) {
    case 0:    f = "Workstation"; break;
    case 0x03: f = "Client?"; break;
    case 0x20: f = "Server"; break;
    case 0x1d: f = "Master Browser"; break;
    case 0x1b: f = "Domain Controller"; break;
    case 0x1e: f = "Browser Server"; break;
    default:   f = "Unknown"; break;
    }
    return(f);
}

void
print_data(const unsigned char *buf, int len)
{
    int i = 0;

    if (len <= 0)
        return;
    printf("[%03X] ", i);
    for (i = 0; i < len; /*nothing*/) {
        printf("%02X ", buf[i] & 0xff);
        i++;
        if (i%8 == 0)
            printf(" ");
        if (i % 16 == 0) {
            print_asc(&buf[i - 16], 8);
            printf(" ");
            print_asc(&buf[i - 8], 8);
            printf("\n");
            if (i < len)
                printf("[%03X] ", i);
        }
    }
    if (i % 16) {
        int n;

        n = 16 - (i % 16);
        printf(" ");
        if (n>8)
            printf(" ");
        while (n--)
            printf("   ");

        n = SMBMIN(8, i % 16);
        print_asc(&buf[i - (i % 16)], n);
        printf(" ");
        n = (i % 16) - n;
        if (n > 0)
            print_asc(&buf[i - n], n);
        printf("\n");
    }
}


static void
write_bits(unsigned int val, const char *fmt)
{
    const char *p = fmt;
    int i = 0;

    while ((p = strchr(fmt, '|'))) {
        size_t l = PTR_DIFF(p, fmt);
        if (l && (val & (1 << i)))
            printf("%.*s ", (int)l, fmt);
        fmt = p + 1;
        i++;
    }
}

/* convert a UCS2 string into iso-8859-1 string */
static const char *
unistr(const u_char *s, int *len, int use_unicode)
{
    static char buf[1000];
    int l=0;

    if (!use_unicode) {
        *len = strlen((const char *)s) + 1;
        return (const char *)s;
    }

    /*
     * Skip padding that puts the string on an even boundary.
     */
    if (((s - startbuf) % 2) != 0)
        s++;

    *len = 0;

    if (s[0] == 0 && s[1] != 0) {
        s++;
        *len = 1;
    }

    while (l < (int)(sizeof(buf) - 1) && s[0] && s[1] == 0) {
        buf[l] = s[0];
        s += 2;
        l++;
        *len += 2;
    }
    buf[l] = 0;
    *len += 2;
    return buf;
}

static const u_char *
smb_fdata1(const u_char *buf, const char *fmt, const u_char *maxbuf,
    int unicodestr)
{
    int reverse = 0;
    const char *attrib_fmt = "READONLY|HIDDEN|SYSTEM|VOLUME|DIR|ARCHIVE|";
    int len;

    while (*fmt && buf<maxbuf) {
        switch (*fmt) {
        case 'a':
            write_bits(buf[0], attrib_fmt);
            buf++;
            fmt++;
            break;

        case 'A':
            write_bits(EXTRACT_LE_16BITS(buf), attrib_fmt);
            buf += 2;
            fmt++;
            break;

        case '{':
          {
            char bitfmt[128];
            char *p;
            int l;

            p = strchr(++fmt, '}');
            l = PTR_DIFF(p, fmt);

            if ((unsigned int)l > sizeof(bitfmt) - 1)
                    l = sizeof(bitfmt)-1;

            strncpy(bitfmt, fmt, l);
            bitfmt[l] = '\0';
            fmt = p + 1;
            write_bits(buf[0], bitfmt);
            buf++;
            break;
          }

        case 'P':
          {
            int l = atoi(fmt + 1);
            buf += l;
            fmt++;
            while (isdigit((unsigned char)*fmt))
                fmt++;
            break;
          }
        case 'r':
            reverse = !reverse;
            fmt++;
            break;
        case 'b':
          {
            unsigned int x;
            TCHECK(buf[0]);
            x = buf[0];
            printf("%u (0x%x)", x, x);
            buf += 1;
            fmt++;
            break;
          }
        case 'd':
          {
            unsigned int x;
            TCHECK2(buf[0], 2);
            x = reverse ? EXTRACT_16BITS(buf) :
                          EXTRACT_LE_16BITS(buf);
            printf("%d (0x%x)", x, x);
            buf += 2;
            fmt++;
            break;
          }
        case 'D':
          {
            unsigned int x;
            TCHECK2(buf[0], 4);
            x = reverse ? EXTRACT_32BITS(buf) :
                          EXTRACT_LE_32BITS(buf);
            printf("%d (0x%x)", x, x);
            buf += 4;
            fmt++;
            break;
          }
        case 'L':
          {
            u_int64_t x;
            TCHECK2(buf[0], 8);
            x = reverse ? EXTRACT_64BITS(buf) :
                          EXTRACT_LE_64BITS(buf);
            printf("%" PRIu64 " (0x%" PRIx64 ")", x, x);
            buf += 8;
            fmt++;
            break;
          }
        case 'M':
          {
            /* Weird mixed-endian length values in 64-bit locks */
            u_int32_t x1, x2;
            u_int64_t x;
            TCHECK2(buf[0], 8);
            x1 = reverse ? EXTRACT_32BITS(buf) :
                           EXTRACT_LE_32BITS(buf);
            x2 = reverse ? EXTRACT_32BITS(buf + 4) :
                           EXTRACT_LE_32BITS(buf + 4);
            x = (((u_int64_t)x1) << 32) | x2;
            printf("%" PRIu64 " (0x%" PRIx64 ")", x, x);
            buf += 8;
            fmt++;
            break;
          }
        case 'B':
          {
            unsigned int x;
            TCHECK(buf[0]);
            x = buf[0];
            printf("0x%X", x);
            buf += 1;
            fmt++;
            break;
          }
        case 'w':
          {
            unsigned int x;
            TCHECK2(buf[0], 2);
            x = reverse ? EXTRACT_16BITS(buf) :
                          EXTRACT_LE_16BITS(buf);
            printf("0x%X", x);
            buf += 2;
            fmt++;
            break;
          }
        case 'W':
          {
            unsigned int x;
            TCHECK2(buf[0], 4);
            x = reverse ? EXTRACT_32BITS(buf) :
                          EXTRACT_LE_32BITS(buf);
            printf("0x%X", x);
            buf += 4;
            fmt++;
            break;
          }
        case 'S':
        case 'R':       /* like 'S', but always ASCII */
          {
            /*XXX unistr() */
            printf("%.*s", (int)PTR_DIFF(maxbuf, buf),
                unistr(buf, &len, (*fmt == 'R') ? 0 : unicodestr));
            buf += len;
            fmt++;
            break;
          }
        case 'Z':
        case 'Y':       /* like 'Z', but always ASCII */
          {
            if (*buf != 4 && *buf != 2)
                printf("Error! ASCIIZ buffer of type %u (safety=%lu)\n", *buf,
                    (unsigned long)PTR_DIFF(maxbuf, buf));
            printf("%.*s", (int)PTR_DIFF(maxbuf, buf + 1),
                unistr(buf + 1, &len, (*fmt == 'Y') ? 0 : unicodestr));
            buf += len + 1;
            fmt++;
            break;
          }
        case 's':
          {
            int l = atoi(fmt + 1);
            printf("%-*.*s", l, l, buf);
            buf += l;
            fmt++;
            while (isdigit((unsigned char)*fmt))
                fmt++;
            break;
          }
        case 'h':
          {
            int l = atoi(fmt + 1);
            while (l--)
                printf("%02x", *buf++);
            fmt++;
            while (isdigit((unsigned char)*fmt))
                fmt++;
            break;
          }
        case 'n':
          {
            int t = atoi(fmt+1);
            char nbuf[255];
            int name_type;
            int len;

            switch (t) {
            case 1:
                name_type = name_extract(startbuf, PTR_DIFF(buf, startbuf),
                    maxbuf, nbuf);
                if (name_type < 0)
                    goto trunc;
                len = name_len(buf, maxbuf);
                if (len < 0)
                    goto trunc;
                buf += len;
                printf("%-15.15s NameType=0x%02X (%s)", nbuf, name_type,
                    name_type_str(name_type));
                break;
            case 2:
                name_type = buf[15];
                printf("%-15.15s NameType=0x%02X (%s)", buf, name_type,
                    name_type_str(name_type));
                buf += 16;
                break;
            }
            fmt++;
            while (isdigit((unsigned char)*fmt))
                fmt++;
            break;
          }
        case 'T':
          {
            time_t t;
            struct tm *lt;
            const char *tstring;
            u_int32_t x;
            x = EXTRACT_LE_32BITS(buf);

            switch (atoi(fmt + 1)) {
            case 1:
                if (x == 0 || x == 0xFFFFFFFF)
                    t = 0;
                else
                    t = make_unix_date(buf);
                buf += 4;
                break;
            case 2:
                if (x == 0 || x == 0xFFFFFFFF)
                    t = 0;
                else
                    t = make_unix_date2(buf);
                buf += 4;
                break;
            case 3:
                t = interpret_long_date(buf);
                buf += 8;
                break;
            }
            if (t != 0) {
                lt = localtime(&t);
                if (lt != NULL)
                    tstring = asctime(lt);
                else
                    tstring = "(Can't convert time)\n";
            } else
                tstring = "NULL\n";
            printf("%s", tstring);
            fmt++;
            while (isdigit((unsigned char)*fmt))
                fmt++;
            break;
          }
        default:
            putchar(*fmt);
            fmt++;
            break;
        }
    }

    if (buf >= maxbuf && *fmt)
        printf("END OF BUFFER\n");

    return(buf);

trunc:
    printf("\n");
    printf("WARNING: Short packet. Try increasing the snap length\n");
    return(NULL);
}

const u_char *
smb_fdata(const u_char *buf, const char *fmt, const u_char *maxbuf,
    int unicodestr)
{
    static int depth = 0;
    char s[128];
    char *p;

    while (*fmt) {
        switch (*fmt) {
        case '*':
            fmt++;
            while (buf < maxbuf) {
                const u_char *buf2;
                depth++;
                buf2 = smb_fdata(buf, fmt, maxbuf, unicodestr);
                depth--;
                if (buf2 == NULL)
                    return(NULL);
                if (buf2 == buf)
                    return(buf);
                buf = buf2;
            }
            return(buf);

        case '|':
            fmt++;
            if (buf >= maxbuf)
                return(buf);
            break;

        case '%':
            fmt++;
            buf = maxbuf;
            break;

        case '#':
            fmt++;
            return(buf);
            break;

        case '[':
            fmt++;
            if (buf >= maxbuf)
                return(buf);
            memset(s, 0, sizeof(s));
            p = strchr(fmt, ']');
            if ((size_t)(p - fmt + 1) > sizeof(s)) {
                /* overrun */
                return(buf);
            }
            strncpy(s, fmt, p - fmt);
            s[p - fmt] = '\0';
            fmt = p + 1;
            buf = smb_fdata1(buf, s, maxbuf, unicodestr);
            if (buf == NULL)
                return(NULL);
            break;

        default:
            putchar(*fmt);
            fmt++;
            fflush(stdout);
            break;
        }
    }
    if (!depth && buf < maxbuf) {
        size_t len = PTR_DIFF(maxbuf, buf);
        printf("Data: (%lu bytes)\n", (unsigned long)len);
        print_data(buf, len);
        return(buf + len);
    }
    return(buf);
}

typedef struct {
    const char *name;
    int code;
    const char *message;
} err_code_struct;

/* Dos Error Messages */
static err_code_struct dos_msgs[] = {
    { "ERRbadfunc", 1, "Invalid function." },
    { "ERRbadfile", 2, "File not found." },
    { "ERRbadpath", 3, "Directory invalid." },
    { "ERRnofids", 4, "No file descriptors available" },
    { "ERRnoaccess", 5, "Access denied." },
    { "ERRbadfid", 6, "Invalid file handle." },
    { "ERRbadmcb", 7, "Memory control blocks destroyed." },
    { "ERRnomem", 8, "Insufficient server memory to perform the requested function." },
    { "ERRbadmem", 9, "Invalid memory block address." },
    { "ERRbadenv", 10, "Invalid environment." },
    { "ERRbadformat", 11, "Invalid format." },
    { "ERRbadaccess", 12, "Invalid open mode." },
    { "ERRbaddata", 13, "Invalid data." },
    { "ERR", 14, "reserved." },
    { "ERRbaddrive", 15, "Invalid drive specified." },
    { "ERRremcd", 16, "A Delete Directory request attempted to remove the server's current directory." },
    { "ERRdiffdevice", 17, "Not same device." },
    { "ERRnofiles", 18, "A File Search command can find no more files matching the specified criteria." },
    { "ERRbadshare", 32, "The sharing mode specified for an Open conflicts with existing FIDs on the file." },
    { "ERRlock", 33, "A Lock request conflicted with an existing lock or specified an invalid mode, or an Unlock requested attempted to remove a lock held by another process." },
    { "ERRfilexists", 80, "The file named in a Create Directory, Make New File or Link request already exists." },
    { "ERRbadpipe", 230, "Pipe invalid." },
    { "ERRpipebusy", 231, "All instances of the requested pipe are busy." },
    { "ERRpipeclosing", 232, "Pipe close in progress." },
    { "ERRnotconnected", 233, "No process on other end of pipe." },
    { "ERRmoredata", 234, "There is more data to be returned." },
    { NULL, -1, NULL }
 };

/* Server Error Messages */
err_code_struct server_msgs[] = {
    { "ERRerror", 1, "Non-specific error code." },
    { "ERRbadpw", 2, "Bad password - name/password pair in a Tree Connect or Session Setup are invalid." },
    { "ERRbadtype", 3, "reserved." },
    { "ERRaccess", 4, "The requester does not have the necessary access rights within the specified context for the requested function. The context is defined by the TID or the UID." },
    { "ERRinvnid", 5, "The tree ID (TID) specified in a command was invalid." },
    { "ERRinvnetname", 6, "Invalid network name in tree connect." },
    { "ERRinvdevice", 7, "Invalid device - printer request made to non-printer connection or non-printer request made to printer connection." },
    { "ERRqfull", 49, "Print queue full (files) -- returned by open print file." },
    { "ERRqtoobig", 50, "Print queue full -- no space." },
    { "ERRqeof", 51, "EOF on print queue dump." },
    { "ERRinvpfid", 52, "Invalid print file FID." },
    { "ERRsmbcmd", 64, "The server did not recognize the command received." },
    { "ERRsrverror", 65, "The server encountered an internal error, e.g., system file unavailable." },
    { "ERRfilespecs", 67, "The file handle (FID) and pathname parameters contained an invalid combination of values." },
    { "ERRreserved", 68, "reserved." },
    { "ERRbadpermits", 69, "The access permissions specified for a file or directory are not a valid combination.  The server cannot set the requested attribute." },
    { "ERRreserved", 70, "reserved." },
    { "ERRsetattrmode", 71, "The attribute mode in the Set File Attribute request is invalid." },
    { "ERRpaused", 81, "Server is paused." },
    { "ERRmsgoff", 82, "Not receiving messages." },
    { "ERRnoroom", 83, "No room to buffer message." },
    { "ERRrmuns", 87, "Too many remote user names." },
    { "ERRtimeout", 88, "Operation timed out." },
    { "ERRnoresource", 89, "No resources currently available for request." },
    { "ERRtoomanyuids", 90, "Too many UIDs active on this session." },
    { "ERRbaduid", 91, "The UID is not known as a valid ID on this session." },
    { "ERRusempx", 250, "Temp unable to support Raw, use MPX mode." },
    { "ERRusestd", 251, "Temp unable to support Raw, use standard read/write." },
    { "ERRcontmpx", 252, "Continue in MPX mode." },
    { "ERRreserved", 253, "reserved." },
    { "ERRreserved", 254, "reserved." },
    { "ERRnosupport", 0xFFFF, "Function not supported." },
    { NULL, -1, NULL }
};

/* Hard Error Messages */
err_code_struct hard_msgs[] = {
    { "ERRnowrite", 19, "Attempt to write on write-protected diskette." },
    { "ERRbadunit", 20, "Unknown unit." },
    { "ERRnotready", 21, "Drive not ready." },
    { "ERRbadcmd", 22, "Unknown command." },
    { "ERRdata", 23, "Data error (CRC)." },
    { "ERRbadreq", 24, "Bad request structure length." },
    { "ERRseek", 25 , "Seek error." },
    { "ERRbadmedia", 26, "Unknown media type." },
    { "ERRbadsector", 27, "Sector not found." },
    { "ERRnopaper", 28, "Printer out of paper." },
    { "ERRwrite", 29, "Write fault." },
    { "ERRread", 30, "Read fault." },
    { "ERRgeneral", 31, "General failure." },
    { "ERRbadshare", 32, "A open conflicts with an existing open." },
    { "ERRlock", 33, "A Lock request conflicted with an existing lock or specified an invalid mode, or an Unlock requested attempted to remove a lock held by another process." },
    { "ERRwrongdisk", 34, "The wrong disk was found in a drive." },
    { "ERRFCBUnavail", 35, "No FCBs are available to process request." },
    { "ERRsharebufexc", 36, "A sharing buffer has been exceeded." },
    { NULL, -1, NULL }
};

static struct {
    int code;
    const char *class;
    err_code_struct *err_msgs;
} err_classes[] = {
    { 0, "SUCCESS", NULL },
    { 0x01, "ERRDOS", dos_msgs },
    { 0x02, "ERRSRV", server_msgs },
    { 0x03, "ERRHRD", hard_msgs },
    { 0x04, "ERRXOS", NULL },
    { 0xE1, "ERRRMX1", NULL },
    { 0xE2, "ERRRMX2", NULL },
    { 0xE3, "ERRRMX3", NULL },
    { 0xFF, "ERRCMD", NULL },
    { -1, NULL, NULL }
};

/*
 * return a SMB error string from a SMB buffer
 */
char *
smb_errstr(int class, int num)
{
    static char ret[128];
    int i, j;

    ret[0] = 0;

    for (i = 0; err_classes[i].class; i++)
        if (err_classes[i].code == class) {
            if (err_classes[i].err_msgs) {
                err_code_struct *err = err_classes[i].err_msgs;
                for (j = 0; err[j].name; j++)
                    if (num == err[j].code) {
                        snprintf(ret, sizeof(ret), "%s - %s (%s)",
                            err_classes[i].class, err[j].name, err[j].message);
                        return ret;
                    }
            }

            snprintf(ret, sizeof(ret), "%s - %d", err_classes[i].class, num);
            return ret;
        }

    snprintf(ret, sizeof(ret), "ERROR: Unknown error (%d,%d)", class, num);
    return(ret);
}